Underwater sound propagation: 49 years with L. M. Brekhovskikh’s Waves in Layered Media

Abstract

In his first 10 years of research on wave propagation in layered media, L. M. Brekhovskikh created a theory that remains a basis for physical understanding and mathematical modeling of underwater sound propagation. Summarized in his celebrated book Waves in Layered Media, first published in 1957, the theory includes spectral (quasi-plane wave) representations of wave fields, normal mode theory for open waveguides, extensions of the ray and WKBJ methods, and a clear treatment of diffraction phenomena attendant to caustics, lateral waves, and reflection of wave beams and pulses. The book also charted the ways forward that have been and are followed by numerous researchers around the globe. Some of the resulting progress was documented in subsequent editions of Waves in Layered Media and in later books L. M. Brekhovskikh coauthored with his students. This paper will discuss diverse, groundbreaking contributions L. M. Brekhovskikh made to the wave propagation theory from the prospective offered by recent developments in underwater acoustics.